Conventional methods for detecting microorganisms such as bacteria and fungus include a direct microscopic count method wherein a specimen is microscopically examined after being pretreated and a cultivation examination method wherein the specimen is examined after cultivating the microorganisms. The direct microscopic count method is often used at medical sites in particular due to convenience.
As known methods for pretreatment in the direct microscopic count method, a potassium hydroxide method, dimethylsulfoxide (DMSO)-potassium hydroxide method, and Parker ink-potassium hydroxide method can be given (Hideyo Yamaguchi et al., Report of the Standardization Committee of the Japanese Society for Medical Mycology, “Jpn. J. Med. Mycol.”, 1995, Vol. 36, pp. 61-86).
Since the potassium hydroxide and DMSO-potassium hydroxide methods do not stain the microorganism, there are problems such as difficulty in detecting Malassezia and requirement of skill in the detection under a microscope. Although the microorganism are stained in the Parker ink-potassium hydroxide method, the method has a problem of requiring a long time for staining from several hours to overnight. There are also problems that the type of ink that can be used in this staining method is restricted. Since the ink itself is comprised of several components, stainability of the bacteria may change according to the composition of the ink.
Therefore, in order to overcome the problems during pretreatment in the conventional direct microscopic count method, an objective of the present invention is to provide a staining agent that can stain microorganisms rapidly and a microorganism staining and detection method using the same.